There are three main types of fees that may be charged on Demex.
Trading Fees: Every executed trade has a commission levied on it. This fee can be reduced (even giving a rebate) via staking.
Network Fees: Most actions on Demex require a nominal network fee (<$0.01) for using the underlying network (Carbon) that the DEX runs on. The fee is paid as consideration to the decentralized network of validators that validate every transaction (e.g. order) placed on Demex.